From: Matthew Wilcox (Matthew.Wilcox@genedata.com)
Date: 03/24/99-04:27:59 PM Z
Date: Wed, 24 Mar 1999 23:27:59 +0100 From: Matthew Wilcox <Matthew.Wilcox@genedata.com> Subject: Re: NFSv4 wishlist Message-ID: <19990324232759.D397@mencheca.ch.genedata.com> On Wed, Mar 24, 1999 at 01:13:02PM -0800, Daniel Quinlan wrote: > - filehandle-related issues > > - fewer (or no) cases where stale filehandles are possible, even > on odd servers using weird underlying filesystems. > - required lookup after rename and any other operations where the > server may want to change the filehandle Bad - other clients don't know that the lookup is required, so this doesn't solve anything. > - way for server to change any or all filehandles (after reboot)? I quite like this idea. Keep a `reboot count' in the filehandle, and the server can return an EREBOOTED to any filehandle which was from a previous session which indicates the client should attempt to lookup the path it had for the file. Not perfect, but a lot better than nothing. > Not wanted in NFSv4: > - Bad performance. :-) This is why I disagree with Rob Thurlow's metadata proposal. I maintain (with absolutely no data to back me up of course) that processing the types of data which have been requested will take a non-trivial amount of CPU and just don't fit with how any OS I know requests metadata. Are there any OSes in existance which don't do the equivalent of saying `fill in this stat structure'? For different types of structure, of course. Yes, you can argue that a server can preprocess the types of data it's being asked for frequently, but why don't we do this at the protocol definition step? If `ultimate flexibility' is still the key goal, then I think the client should tell the server which structures it is interested in, and then only talk in terms of those structures. I think per-request arbitrary metadata is a bad idea. It's just too complex. -- Matthew Wilcox <willy@bofh.ai> "I decry the current tendency to seek patents on algorithms. There are better ways to earn a living than to prevent other people from making use of one's contributions to computer science." -- Donald E. Knuth, TAoCP vol 3
This archive was generated by hypermail 2.1.2 : 03/04/05-01:46:55 AM Z CST